Quantitative resistance level (MIC) of Escherichia coli isolated from calves and pigs suffering from enteritis: national resistance monitoring by the BVL

Abstract

National Resistance Monitoring of the Federal Office of Consumer Protection and Food Safety (BVL), which was put into service in 2001, has made it possible to implement a valid and representative database on the basis of which the resistance situation, development and spread in animal pathogens can be evaluated. Escherichia coil (E. coli) strains originating from calves and pigs suffering from enteritis were first included in the investigations in the 2004/2005 study. A total of 258 bovine and 492 porcine E. coli strains were tested using the broth microdilution method to determine the in vitro susceptibility (minimum inhibitory concentration) to 23 (fattening pigs) and 28 (calves, piglets, weaners) different antimicrobial substances. Considerable prevalences of resistance were found for some antimicrobials. The strains originating from both animal species displayed high prevalences of resistance for tetracycline, trimethoprim, trimethoprim/sulfamethoxazole, doxycycline and ampicillin. Reduced susceptibility was detected particularly in the E. coli strains from calves. The data reveal that the resistance level of E. coli strains isolated from cases of enteric disease in calves and pigs is altogether higher than has so far been reported in pathogens causing different diseases and in other food-producing animal species. Based on the results presented, it is possible to assess the current resistance situation for E. coli strains in calves and pigs in Germany. This in turn helps to deduce the necessary management measures that can be taken in order to minimise resistance to antibiotics. Furthermore, the data help to decide on adequate therapy of E. coli infections of the intestinal tract in calves and pigs and encourage the responsible use of antibiotics in the interests of animal health and consumer protection.